<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>toggle-jquery1.9</title>
<script src="jquery.min.js" type="text/javascript"></script> 
    <style>
        div.container {
            height: 320px;
            border: 1px solid #ccc;
        }
        div.left {
            width: 200px;
            height: 300px;
            background-color: #36f;
        }
    </style>
</head>
<body>
    <div class="container">
        <div class="left"></div>
    </div>
    <button id="toggle">toggle</button>
    <script>
        $(document).ready(function(){
            $('#toggle').click(function(){
                $('.left').animate({width:'toggle'},350);
            });
        });
    </script>
</body>
</html>